@KahleenCuthaldWhile most robots created to serve do serve, Nexus was created... But never given directives or a proper AI matrix. It was developed as a shell for a human conscious, it developed its "conscious" as a will of self-preservation. "Life" literally spawned from jumbled code in a computer, and transferred itself into Nexus, propagating hundreds of times to create the machine as you know it.
I do see what you mean. Rolands expects a droid that will bark if you ask it to. But nexus has to run that bark command through what is basically, a committee of a couple hundred people to see if its a logical, proper action to make. And with how long the machine has researched alone, and all it's accomplished, barking is beneath it.